<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    * {
        margin: 0;
        padding: 0;
    }
    
    #id {
        width: 200px;
        height: 200px;
        position: relative;
    }
    
    #id:before {
        content: "";
        /* position: abs; */
        position: absolute;
        left: 0;
        bottom: 0;
        width: 100%;
        height: 1px;
        background-color: #000;
    }
    
    @media screen and (-webkit-min-device-pixel-ratio:2) {
        #id:before {
            transform: scaleY(0.5);
        }
    }
    
    @media screen and (-webkit-min-device-pixel-ratio:3) {
        #id:before {
            transform: scaleY(0.5);
        }
    }
</style>

<body>
    <div id="id"></div>
</body>

</html>